DE1959668A1 - Adhesive solutions for polyester tire cord - Google Patents

Description

In U.S. Patent 3,285,938 relating to tetraglycidyl ether from tris (hydroxybenzyl) phenol, becomes an intermediate product for such ethers, namely the resin former Tris (hydroxybenzyl) phenol. Specific properties of tris (hydroxybenzyl) phenol are not specified, but this known compound is allegedly at room temperature a resinous product. The compound is generally by reacting 1 mole of trimethy ^ olphenol with 3 moles Phenol made.

It is known that polyester fibers have many desirable properties as reinforcement for rubber articles. Polyester fibers have high tensile strength, absorb less moisture than nylon or rayon, and stretch less than other fibers, giving the reinforced articles greater dimensional stability. Polyester fibers are also more heat resistant than nylon or rayon fibers. Joining polyester cord with rubber, however, was due to the difficulty

009824/1931

correct wetting and penetration of the fiber to achieve has been problematic. When joining polyester cord with rubber, problems such as insufficient Adhesion, low heat resistance, low flex life and difficult application can be overcome.

It has now been found that adhesive solutions for connecting polyester fibers with rubber ("rubber stock") from aqueous Rubber latices and 10 to 50 parts tris (hydroxybenzyl) phenol per 100 parts of rubber can be produced. The effectiveness of these polyester cord adhesive solutions is particular surprising in view of the fact that Tris (monohydroxyfe benzyl) phenol-containing adhesive solutions are unsuitable for joining nylon or rayon cord.

An adhesive solution for bonding polyester fibers to rubber can be prepared by adding an aqueous rubber latex, Tris (monohydroxybenzyl) phenol in an amount of about 10 to 50 parts per 100 parts of rubber in the latex, one to adjust a pH between about 10.0 and 13.5 Sufficient amount of alkali and enough water to give the solution a solids content of about 8 to 25% by weight, is mixed.

The new adhesive solutions according to the invention contain Tris (mono- * hydroxybenzyl) phenol. Tris (monohydroxybenzyl) phenol and a ■ Process for its manufacture are in the US patent 3,285,938. In this the compound is used as an intermediate in the production of glycidyl ethers. Tris (monohydroxybenzyl) phenol can by the process described in said patent or by other suitable processes from phenol and trimethylolphenol or tris (methoxymethyl) phenol duroh acid catalyzed condensation getting produced.

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BATH ORIGINAL

The adhesive solution is prepared by adding an aqueous mixture is formed from a suitable rubber latex and tris (monohydroxybenzyl) phenol. The tris (monohydroxybenzyl) phenol will preferably diluted with enough water to reduce the concentration, and the latex is then added to the aqueous solution admitted.

The rubber latex that can be used in the adhesive solutions according to the invention is of the kind of the usual rubber latices, like them used in the manufacture of rubber adhesive solutions. Such latices are e.g. vinylpyridine-styrene-butadiene terpolymer latices, e.g. hot-polymerized (2000 Series) styrene-butadiene latices, cold-polymerized (2100 Series) Styrene-butadiene latices, natural latex, regenerated rubber dispersions, butyl rubber dispersions or ethylene-propylene-butadiene terpolymer rubber dispersions.

The ratio of resin to rubber in the adhesive solutions should be in the range of between about 10 to 50 parts resin former per 100 parts rubber solids (i.e. based on the amount of dry rubber in the latex). Less than about 10 parts cause insufficient adhesion, while larger ones Amounts than about 50 parts resin per 100 parts rubber are uneconomical.

The adhesive resin solution usually contains about 8-25? 6 solids in aqueous solution. Preferably about 10% total solids are used in the aqueous mixture, with additional water optionally being added to achieve the desired solids level. The term "solids ¹¹ " used in indicating the solids content of the solution is used to define the amount of rubber and resin added, ie the non-volatile part of the solution.

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ORföliSfAc

The aqueous solutions according to the invention should be adjusted to a pH between approximately 10.0 to 13.5. One such pH adjustment can be achieved by adding an aqueous alkali such as sodium hydroxide or ammonium hydroxide to the adhesive solution can be carried out up to the desired pH. However, if the composition has an addition of vinyl pyridine latex (pH 10.2), no further adjustment of the pH of the solution is necessary. Too high pH values should be avoided because of the risk of attack on the fiber material used in the cord.

The one coated with the adhesive solution according to the invention by dipping Cord can be used with various types of rubber substrates, such as natural rubber, styrene-butadiene rubber, Polybutadiene, butyl-ethylene-propylene terpolymers and the new synthetic-natural polyisoprene caoutchouks are connected.

While the polyester tire cord is dipped, it is treated under tension with the adhesive solution in a latex dipping device. The dipped cord is then dried for about 60 to 240 seconds at about 204 ^° C. to 260 ^° C., applied to the rubber and cured.

For the treatment of Polyesterreifenkords a conventional dipping apparatus is employed, wherein a cord is continuously pulled through a Röilensystem daa by immersion bath. The minimum material tension is applied during the passage through the immersion bath, which leads to a maximum of moisture absorption, excess immersion solution is removed by treating the cord material in an air jet or by vibration or passing it between guomi rollers, after which the cord is passed through a hot air tunnel is passed in order to dry this and to bring it ^{to a temperature above 204 0} C to eu about 260 ⁰ O. The preferred temperature is about ₉ and an upper limit for the curing temperature is let da.nn

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ORlQINAL

achieved when the polyester tire cord deteriorates due to caused by the increased temperature.

During the heat drying step of the process, the cord is stretched approximately 3 "to 4 $ and treated for sufficient time to set the coating on the cord. The time required for the cure cycle should include an additional cure time for making the dip coating of the polyester cord, a treatment time of about 120 seconds (232 ^° C) is suitable.

The static adhesion test measures whether there is a sufficient bond between rubber and tire cord. The Η test is used by the rubber industry to determine the static adhesion of textile cord to rubber has been applied. This test, named ASTM D2138-67, was made applied when testing the adhesive solutions according to the invention. The Η test provides a method for measuring the necessary Force to pull a single cord axially from a 'small rubber block in which it is embedded, to pull. Ideally, the shear strength would be the adhesive layer / rubber or the adhesive layer / cord (inner base area) can be measured. In these attempts, two form small Rubber blocks with a connecting cord a test piece that resembles the letter H, according to which the test is named. The separation is brought about by pulling the samples apart with two-hood clamps, wherein it is determined when the connection in one of the blocks is disconnected. With the data, of course, is the size of the sample and the temperature at which the test was carried out has been taken into account. .

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BAD ORIGJNAU

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The invention is illustrated in more detail by the following examples, with the parts indicated, unless otherwise indicated, parts by weight are:

example 1

Tris (monohydroxybenzyl) phenol were prepared according to the procedure as it is described in Example I, Part A, of U.S. Patent 3,285,938.

An adhesive dipping solution for polyester tire cord was prepared, by 4.6 parts of the above product, 67.37 parts of water and 28.03 parts of a commercially available Terpolymer latex (vinylpyridine-styrene-butadiene, Gen-Tac-latex, 41 $ solids) were mixed. The received Solution had a total solids content of $ 15.3 and one Resin to rubber ratio of 1: 2.5. The pH had to be adjusted to about 10.6 for a stable dispersion of all components. This solution was named Adhesive Solution A. Three other solutions (B-D) were made prepared as described above, but the pH values modified with 10 # aqueous sodium hydroxide.

Five solutions (EI) were made using the composition of solution A, but the tris (hydroxybenzyl) phenol was replaced with a conventional resorcinol-formaldehyde resin. The resorcinol-formaldehyde resin used was prepared according to the method of US Pat. No. 2,385,372. The solutions were adjusted to various pH values with 10% aqueous sodium hydroxide. The solutions (AI) of (3-stringy execution, 10.3 / 10.3 Twist Dacron T-68, 1000 Denier) used in Polyesterreifenkord and the dipped cord for two minutes cured at 232 ⁰ O, and connected to standard natural rubber «The so connected block became that

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BATH

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Example 2 ;

An adhesive dipping solution for polyester tire cord was prepared by mixing 4.6 parts of the tris (monohydroxybenzyl) phenol prepared in Example 1 and 67.37 parts of water. Then 1.15 parts of formaldehyde were (37 $ aqueous solution) _r added. After curing for two hours at room temperature, 28.03 parts of commercially available latex (vinylpyridine-styrene-butadiene, Gen-Tac latex, 41% pesticides) were added. This solution was named Adhesive Solution A-. A second solution (B) was prepared as described above, except that the tris (monohydroxybenzyl) phenol of solution A was replaced by a conventional resorcinol-formaldehyde resin prepared according to US Pat. No. 2,385,372. The solutions were used to bond polyester tire cord to natural rubber by the method of Example 1. The results of the Η test are given in Table II:

Table II

Adhesive release

AWAY

pH-value percentage state of the H-test (6.35 mm) of the solution uptake of the hardened kg at 100 ± 1 ° G Bades Films

10 ", 92 8.51

6.39
4.33

very sticky 6.81 slightly sticky 5.40

From the table it can be seen that the addition of formaldehyde with tris (monohydroxybenzyl) phenol has better adhesion than a resorcinol-formaldehyde resin results. The increased adhesion is shown by an increase in the values of the Η test of about .25 *.

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Claims (2)

Adhesive solution for connecting polyester fibers with rubber, characterized in that it is an aqueous mixture of rubber latex, tris (monohydroxybenzyl) phenol in an amount of about 10 to 50 parts by weight per 100 parts by weight Rubber, an amount of alkali sufficient to provide a pH of about 10 to 13.5, and water, the solids content of the mixture to about 8 to 25 wt. 56 set includes. 2. Use of an adhesive solution according to claim 1 for immersion of polyester tire cord for the manufacture of rubber coated tire cord. 009834/1931